1. Field
Apparatuses and methods consistent with exemplary embodiments relate to acquiring a magnetic resonance (MR) image, and more particularly, to acquiring an MR image that allow setting of a plurality of regions and imaging of an independent MR image for each of the plurality of regions.
2. Description of the Related Art
Magnetic resonance images are obtained by using information determined through resonance of atomic nuclei exposed to a magnetic field. The resonance of atomic nuclei is a phenomenon where an atomic nucleus in a low energy state absorbs radio frequency (RF) energy and is excited to a higher energy state when a specific RF is incident on the atomic nucleus magnetized by an external magnetic field. Atomic nuclei have different resonant frequencies depending on their types, and resonance thereof is affected by the intensity of an external magnetic field. The human body includes a large number of atomic nuclei, and hydrogen nuclei are commonly used for magnetic resonance imaging (MRI).
An MRI system includes a magnet creating a main magnetic field in an imaging space, an RF coil generating an RF signal into the imaging space, and gradient coils creating magnetic field gradients for selecting a region of an object to be imaged from the imaging space. The MRI system applies pulse sequences designed for imaging the object to the RF coil and the gradient coils and acquires an echo signal corresponding to the RF signal generated into the imaging space. Signals output from the RF coil and the gradient coils have errors due to several factors, and these errors in the output signals may degrade a signal-to-noise ratio (SNR) of an MR image and cause artifacts in the MR image.
MRI systems use a noninvasive imaging technique and provide images with superior tissue contrast. In addition, unlike the computed tomography (CT) imaging, MRI images are not affected by bone artifacts. Furthermore, the MRI systems can produce various cross-sectional images in desired directions without changing a position of an object, and thus, they are widely used in many medical areas alone or in conjunction with other imaging diagnostic tools.
When a scout image of an object cannot be obtained by imaging a wide range of the object, it may be difficult to set a precise field of view (FOV). Furthermore, when MR images have to be acquired for different lesions in one object and the lesions are far away from each other although they are in the same local range, multiple MRI scans are required, which is not only time consuming and expensive but also causes adverse health effects due to a high specific absorption rate (SAR).